Plasticity in thermal tolerance has limited potential to buffer ectotherms from global warming

Area of Science:

• Ecology
• Evolutionary Biology
• Physiology

Background:

• Global warming increases overheating risks for ectotherms.
• The potential for thermal tolerance plasticity to mitigate these risks is poorly understood.
• Knowledge gaps exist regarding global and taxonomic patterns of thermal tolerance plasticity.

Purpose of the Study:

• To investigate broad-scale variation in ectotherm thermal tolerance plasticity.
• To test hypotheses explaining patterns of plasticity across diverse taxa and habitats.
• To assess the role of plasticity and acclimation in mitigating overheating risks.

Main Methods:

• Utilized a comprehensive dataset of vertebrate and invertebrate ectotherms.
• Included taxa from terrestrial, freshwater, and marine environments.
• Analyzed variation in heat and cold tolerance plasticity in relation to environmental factors.

Main Results:

• Heat tolerance plasticity was not correlated with latitude or thermal seasonality.
• Cold tolerance plasticity showed associations with thermal seasonality in certain habitats.
• Aquatic ectotherms exhibited roughly twice the plasticity of terrestrial ectotherms.
• All ectotherms demonstrated limited acclimation capacity in thermal tolerance.

Conclusions:

• Limited behavioral thermoregulation may drive greater physiological plasticity (Bogert effect).
• Overheating risk reduction via acclimation is minimal, even in plastic species.
• Behavioral and evolutionary mechanisms are vital for ectotherm adaptation to extreme temperatures.